1. Field of the Invention
The present invention relates to a copying machine controlling system, and particularly to copying machine controlling apparatus functioning as terminal devices and a copying machine controlling system including the copying machine controlling apparatus and a centralized control unit.
2. Description of the Related Art
A system for management of a plurality of copying machines is disclosed in U.S. Pat. No. 4,583,834. In the disclosed system, various operating data of the copying machine such as a total number of copies, machine malfunctions and amounts of remaining copy sheets and toner are transmitted to a computer through a communication network. The computer processes the transmitted data and feeds back to the copying machine instructions.
In a copying machine controlling system in which condition data of each copying machine is collected to a control center through a communication line from each copying machine controlling apparatus as a terminal device, a method of transmitting data from each copying machine controlling apparatus side in data transmission is introduced. This is because not only periodical data collection but also data collection for trouble occurrence of copying machines and so forth are demanded.
Therefore, in the above system, periodical transmission times from respective copying machine controlling apparatus are set different from each other in order to prevent overlapping transmission.
In a timer provided inside each copying machine controlling apparatus, however, an error peculiar to each timer is developed after a long time period, resulting in a cause of the above transmission overlap.
A system is proposed for communication between a central control unit and a terminal device through a network (a public telephone network) in an apparatus equivalent to the above.
In a system in which control data for a plurality of copying machines are transmitted from respective terminal devices to a control unit on the center side through a communication network (a public telephone network) for centralized control, connection between the terminal devices and the control unit on the center side sometimes can not be made.
For example, it is when the network connection can not be made because of overlapping dialing from a number of terminal devices, or when some operational fault occurs in the control unit on the center side.
In such cases, re-dialing may be made after a predetermined time period. In the case where dialing from a great number of terminals overlap, however, in spite of the re-dialing, it is difficult to make connection with the centralized control unit.
Accordingly, the connection with a control center can not be made in some cases even when data communication must be made immediately with the control center side.
As a case where the connection with the central control unit is impossible, for example, occupation of the communication line on the center side due to successive dialings from a large number of communication terminal devices is possible.
In such a case, after a predetermined time period, for example, it is desired to quickly make a connection to the center side by automatic redialing.
Accordingly, general devices and networks such as a telephone machine and a facsimile are usually shared as the above-described communication terminal devices and communication networks.
Accordingly, when the probability of line connection with the center side is low (a large number of dialings are overlapping, for example), it is not preferable to repeat redialing because it occupies the line on the user side in vain to limit use of a telephone machine and the like.
Furthermore, in a system for controlling in a centralized manner a large number of copying machines (precisely speaking, copying machine controlling apparatus connected to respective copying machines) through a communication line, a peculiar fixed time transmission time is assigned to each copying machine controlling apparatus, and a corresponding copying machine controlling apparatus and the centralized control unit are connected with each other at the fixed time transmission time for communication of predetermined data.
Also, not only data communication at the fixed time transmission time, but also data communication required for dealing with a trouble is also made by making a connection with the centralized control unit when a trouble occurs, for example.
As described above, however, the data communication between copying machine controlling apparatus and the centralized control unit is made through a communication line, so that a connection with the centralized control unit can not be made when a telephone machine or the like sharing the communication line is in use even at the fixed time transmission time, for example.
Connection with the centralized control unit can not be made either in data communication between another copying machine controlling apparatus and the centralized control unit when some trouble occurs in another copying machine controlling apparatus.
In such a case, a re-dialing time is automatically set by the copying machine controlling apparatus to call the centralized control unit again at the re-dialing time.
Accordingly, when a fixed time transmission time of a certain copying machine controlling apparatus is set in a time zone in which connection with the centralized control unit is difficult due to some reasons, re-calling of the centralized control unit frequently takes place in the particular copying machine controlling apparatus. This is useless and also prevents use of a telephone machine sharing the communication line by occupying the communication line of the particular user, for example.
The time period in which connection with the centralized controlling unit is difficult includes a time period in which a user of a particular copying machine controlling apparatus frequently uses a telephone machine, a time period in which a trouble is likely to occur ill each copying machine controlling apparatus, and a time period in which a power supply is turned on in each copying machine controlling apparatus and calling frequently takes place like early in the morning.